Sulfonamide Polymers for Uniform Copper Electroplating
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Solution Overview
Problem
Current copper electroplating methods face challenges in achieving uniform copper deposits on substrates with irregular topography, particularly in blind vias and through-holes, and are prone to nodule formation, which can lead to electrical and mechanical issues.
Innovation Solution
A composition comprising copper ions, an electrolyte, and a polymer reaction product of sulfonamides or their salts with epoxides, which acts as a leveling agent to provide uniform copper deposits with improved throwing power and reduced nodules, is used in the electroplating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leveling agents are used in copper electroplating baths, then uniform copper deposits can be achieved on substrate surfaces, but the throwing power is insufficient and nodule formation occurs
Solution Approach 1:
The patent changes the chemical parameters of the leveling agent by using sulfonamide-based polymers with specific functional groups (carboxyl, hydroxyl, amine, or carbonyl) instead of conventional leveling agents. This chemical parameter change enables simultaneous achievement of uniform copper deposits, improved throwing power, and reduced nodule formation, resolving the contradiction between deposit uniformity and reliability
Solution Approach 2:
The patent employs composite material structure by combining sulfonamide backbone with multiple functional groups (carboxyl, hydroxyl, amine, carbonyl) in the polymer chains. This composite molecular structure provides multiple interaction mechanisms with copper ions and substrate surfaces, enabling simultaneous improvement of deposit uniformity, throwing power, and nodule resistance
2Adaptability or versatility
If electroplating is performed on substrates with irregular topography including blind vias and through-holes, then complex interconnect structures can be formed, but voltage drops cause uneven metal deposit thickness
Solution Approach 1:
The sulfonamide-based polymer leveling agent provides local quality control by differentially adsorbing on various substrate surfaces and aperture walls. The polymer's functional groups interact selectively with copper ions at different locations (substrate surface vs. aperture walls), creating localized concentration gradients that compensate for voltage drops and ensure uniform deposit thickness throughout the complex structure
Solution Approach 2:
The sulfonamide-based polymer acts as an intermediary between the electroplating bath and the substrate apertures. It mediates the copper ion deposition process by adsorbing copper ions and releasing them uniformly across the substrate surface and into apertures, preventing direct voltage drop effects from causing uneven deposition
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively deposits copper with a substantially level surface across substrates, including those with small features, enhances throwing power, and improves physical reliability under thermal shock stress while minimizing nodule formation.
Implementation Method 1
Methods for electroplating articles with metal coatings generally involve passing a current between two electrodes in a plating solution where one of the electrodes is the article to be plated
Implementation Method 2
The reaction products provide copper layers having a substantially level surface across a substrate, even on substrates having small features and on substrates having a variety of feature sizes. The plating methods effectively deposit copper on substrates and in blind vias and through-holes such that the copper plating compositions may have good throwing power
Implementation Method 3
copper deposits may have good physical reliability in response to thermal shock stress tests and reduced nodules
Data Source
AI summary
Sulfonamide based polymers are reaction products of sulfonamides and epoxides. The polymers may be used as levelers in copper electroplating baths, to provide good throwing power. Such reaction products may plate copper or copper alloys with good surface properties and good physical reliability.